Brake



Feb. s ,1927; 1,616,586

B. G. LEFERE BRAKE Filed Sept. 21, 1923 annu/woz gena/Vie g @513 awed/Maja 20 ,that the entire toggle mechanism may have 4Patented Feb. 8, 1927.

UNITED STATES PATENT OFFICE.

BENONIE e. LEFERE, or FLINT, MICHIGAN, AssIeI-vo'a To GENERAL MOTORS conroRATIoN, OF DETROIT, MICHIGAN, A CORPORATION or DELAWARE.

BRAKE,

Application led September 21, 1923. Serial lN'o. 664,017.l

This invention rela-tes to brakes and is ilr lustrated as embodied in a full Wrapping internal band brake arranged on the rear Wheel of an automobile. y

One featurejof the invention relates to an improved arrangement of toggle mechanism for brakes of the full wrapping typeto permit the use of a pair of bell crank levers for the toggle links, in such a man1 ner 4as to secure application of the band expanding'force in a substantially circumferential' direction instead of in a direction havinga considerable radial component as with an ordinaryvtoggle. @ne satisfactory form .of the improved toggle. mechanism includes bellcrank levers connected to the opposite Vends of the brake band and jointly connected to an operating device, and a oating rigid fulcrum member on which bot-h of the bell -crank levers are pivotedl so a limited circumferential movement with thebrake band without disturbing4 the rela-4 tive positions of the fulcrums of the bell r crank levers. v e

Other features. of the invention relate to an -arrangement of av full wrapping brake lhaving a support on the open side of the 34 and 36, 1n such a manner as to ellmlnate drum with a stop member such as a bracket mounted on the support and vextending be.

of movement of thc drum, transmits the braking torque to the support; and to a novel band positioning device including a fixed bracket arranged to determine the contracted or idle position of the band and which is slotted to receive an inwardly extending projection on the band to determine its lateral position.

Thesev and other features of the invention, including various novel combinations and desirable particular constructions of parts,

r will be apparent from the following description of the illustrative embodiment shown in the accompanying drawings, in which:

Figure 1 is a vertical section just inside lthe road wheel, and with the side of the drum partly broken away, showing various parts of the brake in side elevation; and

Figure 2 is a section on the lme 2-.2 of Figure 1 showing the mechanism for operating the brake band.

I n the form selected fora illustration the brake comprises a drum` 10 mounted on a road Wheel 12 rotatably supported on a rear axle casing' 14 on which is xedly mounted a stationary support 16 carrying a plate v18 closing the open side of. drum 10.

According to the present invention, an internal full Wrapping, brake band 20 is arranged inside of drum l()4 in such a manner that the braking torque is transmitted by.l

one end or the other of the band, according to which direction the drum is turning, to a bracket 22 havingy oppositely facing .portions extending between the ends of the band and a central portion which is riveted or otherwise secured ,to the support 16. Both ends of the band arefnormally held in engagementwith the bracket by a spring 24. The band is operated by a brake shaft 26 .through suitable driver-controlled connections rocking an arm 28.. Shaft 26 carries a pair of rocker arms 30 pivotally connected by a link 32 to twooppositely extending pairs of bell crank levers A34 and 36 connected to opposite ends, of brake band 20 lat 38 and 40.

, As explained above, one important feature of the invention relates to controlling the direction of operation'of the toggle levers most of the radial component, by providing a r1g1d floatlng fulcrum member such as a curvedlink 42 pivotally connected to bell crank levers 34 at 44 and to bell crank levers 36 at 46. By this arrangement the entire toggle mechanism is free to have a limited 'the band against the drum 10. 'Thus the band is expanded with substantial univ formity.

According to another feature of the invention the idle position of band 2O is determined by brackets 50, three being shown, each of which brackets is riveted or other,- wise secured to the stationary plate 18. Each bracket has a segmental portion or flange y52 extending inslde of brake band l20 to determine'its inner or-idle position, and the segmental portion is slotted as shown in Figure 111-17154' slidngly to receive an inwardly'extending projection 56 riveted or otherwisesecured to band 20, in such a manner as to determine the lateral position of the brake Vband and to prevent the band` from rattling.

v iWhile one illustrative embodiment of myl 4pivotally connected to the band and to each other to constitute-a toggle for voperating the band, means operating on the pivotal conneetion between the bellcrank levers to break and to` straighten the toggle, and a floating memberpivotally connected tofboth bel`l` crank levers and providing fulcrums there- 42. `A. brakecomprising, in combination,

'a drum, an expansibleand contractible band having a limited circumferential movement ywitlrrespect to the drum, stops 'foropposite ends of the band, a pair of levers pivotally connected to the'band and to each other to constitute a toggle for operating the\ band, means operating on the pivotal connection between the levers to break and to straighten the' toggle, and a floating member pivotally connected to both levers at intermediate points andproviding fulcrums therefor.

3. A brake comprising, in combination,

' a drum, an expan'sible and eontractible band vhaving a limited circumferential movement with respect to the drum, stopsy foropposite ends of the band, a pair of bellcrank levers pivotallyconnected to thc band and to. each other to constitute a toggle for operating the baud, a driver-controlled rock arm connected to the pivotal connection between the bellcrank levers, and a rigid floating link pivotally connected at opposite ends to the bellcrank levers to provide angularlyshiftable fulcrums therefor,

4. A Vfull-wrapping bandbrakehaving a pair 'ofband-expanding bellcrank toggle .levers connected by a floatingffulcrum link.

In testimony whereof I affix my signature.

l Bimt'nvni G. LEFRE. 

